Carbon dioxide (carbonic acid anhydride: CO2) has properties of being not only soluble in water (water-soluble) but also soluble in fat (fat-soluble) together, and therefore it has conventionally been known that, if carbon dioxide contacts the skin and mucous membrane of the living organism having both properties of water and fat, carbon dioxide penetrates under a subcutaneous layer of the living organism and expands blood vessels around penetrated parts of carbon dioxide, and works to improve the blood circulation.
Further, if penetrating subcutaneously, carbon dioxide has possibilities of displaying various physiological effects such as expanding the blood vessels, accelerating the blood circulation, dropping blood pressure, improving metabolism or accelerating to remove pain substance or waste products. In addition, it has also anti-inflammation and anti-bacterial. Therefore, carbon dioxide has recently been given attentions also from viewpoints of improving health or beauty other than the purpose of medical cares.
In the organization of the living organism, carbon dioxide works to release oxygen having been carried in combination with hemoglobin in a red blood cell. Around parts at the high concentration of carbon dioxide, the red blood cell releases more oxygen. Thus, supply of oxygen to cells by the red blood cell is mainly controlled by carbon dioxide. In short, being without carbon dioxide, hemoglobin remains as having been combined with oxygen and the cell becomes unable to receive oxygen. Carbon dioxide serves to play in fact very important roles also in metabolism within the living organism. Thus, carbon dioxide is not mere waste products resulted from energy action of the cell, and it has gradually cleared that carbon dioxide exerts various important services in the living organism.
Then, for causing carbon dioxide to be absorbed directly in the skin and mucous membrane of the living organism, various apparatuses have been proposed such as utilization of bath agents for generating carbon dioxide in hot water of a bathtub (for example, refer to patent documents 1 to 3).